I can't tell that it makes much difference In MSI afterburner I can set it at +120 on the core and GPU-z shows 1035 on core and 1100 on boost but when I run a benchmark and look at GPU-z log files it show my clock went up to 1234.5mhz ,does it really manner what you overclock to, if the card is going to get the max it can when it runs .I can run it at default and my 3DMark 11 is P1497 and when I set it to +120 and raise my power limit and voltage ,I get a score of P16345,It hard to get a real score and know what your card is really running,if I set it to 1100mhz and it ends up doing 1234.5mhz